With the increasing proportion of renewable energy represented by wind power and photovoltaic power, the inter-mittence and strong volatility of renewable energy bring many challenges to the safe and stable operation of the power system. In present stage, configuration principle and method of the energy storage battery capacity is one of the problems in practical energy storage engineering constructions. In this paper, smooth new energy grid power fluctuations is taked as the goal, combined with the local wind and light resources, renewable energy power is decomposed and frequency domain information is obtained by discrete Fourier transformation. Battery energy is used to transfer the high-frequency volatility components, a battery energy storage capacity configuration method considering daily power is proposed. Analysis of historical monitoring data of a wind farm in Hami, Xinjiang province verifies the applicability of the proposed method. The results show the proposed method can scientifically configure energy storage capacity according to the grid-connected volatility of renewable energy output and ensure the continuous operation of energy storage, thus provides a guiding significance and practical value for the construction of battery energy storage engineering.